"China is now becoming a headache for Russia." A thread on Sino-Russian relations.

MOSCOW — Chinese President Hu Jintao’s official visit to Russia heralds the significant strides the neighboring giants have made in bilateral relations since the collapse of the Soviet Union. Yet my discussions here over the past week with a range of Russian government officials, businessmen and academics reveal a complex relationship. All in all, as a leading Russian sinologist observed, “China is now becoming a headache for Russia.”

Discussions in Beijing earlier this month also pointed to potential problems on the horizon.

On the surface, President Hu’s meeting with President Dmitri Medvedev will produce the usual accolades of partnership and friendship. But the 20-year honeymoon may be ending, with both countries reverting to their traditional suspicion and competition.

On the positive side, the meeting will point to real achievements in recent years. After nearly two decades of negotiations, the disputed 2,700-mile border has been demarcated. Beijing and Moscow also have concluded numerous bilateral agreements on trade and investment, military affairs, nuclear weapons, energy cooperation, science and technology, cultural exchanges and international policy.

Moscow and Beijing regularly vote in tandem on the United Nations Security Council. Their solidarity has reflected common world views. As a senior Russian Foreign Ministry official put it: “We have either shared or identical views of all international issues.”

But the fact that China’s global equities and responsibilities are growing while Russia’s are minimal and declining may impinge on their solidarity.

Prior to their meeting, Presidents Hu and Medvedev convened two other multilateral forums in the Ural city of Yekaterinburg, forums that China and Russia have introduced to counterbalance the United States in regional and world affairs. One is the Shanghai Cooperation Organization (comprised of China, Russia and five Central Asian Republics); the other is the first official summit of the BRIC group (Brazil, Russia, India, China). While neither grouping carries much clout, they do reflect an effort to pluralize the global order.

Although the dragon and the bear have been getting on in recent years, beneath the surface all is not well. Historically rooted suspicions mix with contemporary tensions — the arms trade, for example, is a central complaint for both.

Since 1989 and the imposition of arms embargoes on China by the United States and European Union, Russia has been Beijing’s principal supplier. Israel and Brazil have made minor contributions to China’s growing arsenal, but Moscow’s sales have been extensive.

These sales ran at approximately $1 billion per year through the 1990s and rose to more than $3 billion per year from 2001-2006, but since 2007 have declined to about $1 billion. Few new contracts have been signed since 2005. The Russians offer a variety of competing explanations, all of which have some validity, but the bottom line is that military sales have plummeted over the past two years.

Russia has other concerns as well. Like most countries, it began to run a growing trade deficit since 2007 and the structure of its trade is dominated (90 percent) by raw materials for low-end manufactures. Many of people in Moscow still speak of the visceral historical Russian fear of Chinese immigrants flooding Siberia and the Russian heartland. Supplies of Siberian gas and oil have also been a thorny issue.

China is also viewed as making inroads into Russia’s “near abroad” in Central Asia and the Caspian region. Beijing’s failure to support Russia’s incursion into Abkhazia and South Ossetia last summer has irked Moscow.

Finally, Russian strategists are very concerned (as are Europeans and Japanese) about recent discussions of a U.S.-China “G-2,” given the Obama administration’s calls for a Sino-American global partnership.

The real challenge for the United States and Europe is to engage both Russia and China in a broader global partnership and to break the Beijing-Moscow duopoly that often splits the U.N. Security Council. The Council’s unanimous condemnation of North Korea last week was a good beginning to an era of global partnership.

David Shambaugh is director of the China Policy Program at George Washington University and a nonresident senior fellow at the Brookings Institution in Washington.